Such a blister-type packaging unit is disclosed in WO-A-01/60711. This publication describes a packaging unit having a so called tear-open strip comprising a part of the circumferential joint. The tear open strip is connected with a remainder part of the packaging unit by a weakened region in both the front wall and the rear wall. The tear-open strip can be separated from the packaging unit by tearing the weakened region by the user. Subsequently, the packaging unit can be easily opened in order to remove the article from the packaging unit.